Tacheometers, the generic term for theodolite/distance measuring instrument combinations, are powerful surveying tools capable of measuring the angles and the distances between points. The major drawback of the prior art in tacheometers has been that a small, lightweight, and highly accurate tacheometer has heretofore been unobtainable.
The present invention utilizes a sinusoidal signal interpolator technique to encode angles as phase shifted signals. The distance module similarly encodes distance as a phase shifted signal, allowing both angle and distance measurements to be decoded by a shared phase detector and accumulator.